Here is my new simple Electronics project about Automatic Street Light Control System or Dark Sensor.
it is a simple and powerful concept , which uses transistor ( BC 547 NPN) as a switch to switch ON and OFF the street light system automatically .
It automatically switches ON lights when the sunlight goes below the visible region of our eyes. ( e.g in evening after Sunset ).
it automatically switches OFF lights when Sunlight fall on it ( e.g in morning ) , by using a sensor called LDR (Light Dependent Resistor) which senses the light just like our eyes.
Needs no manual operation for switching ON and OFF...
Step 1: Things you need...
Show All 7 Items
* 1 BC547 transistor
* 1 220 k resistor
* 1 330 ohms resistor
* 1 LED (any colour )
* 1 9v battery
* 1 battery clip
* 1 LDR ( light dependent resistor )
Step 2: AND...
* Connecting wires
* soldering rod and wire
* wire stripper
Step 3: Circuit diagram
solder the transistor on the board and solder one wire of the LDR to the emitter and other to the base , solder the negative wire of the LED to the base of the transistor with a 330 ohms resistor and also solder 220k resistor with the one side of the 330 ohms resistor .
Step 4: Finsih... Uuuhuuuu... :p
The simple circuit is ready for testing now . Connect 9v battery terminals to the circuit as show in fig and see the output . As you block light falling on Light dependent resistor (LDR), the LED glows .